Mechanical thrombectomy is a procedure which has been in widespread use for many years. Typical thrombectomy devices are balloons which are inflated in a vessel and then withdrawn to pull thrombi into a sheath and then withdrawn from the patient. Other devices are simple open ended catheters into which a thrombus is aspirated and removed from the patient. Another thrombectomy device employs a basket that is opened within the thrombus so that the thrombus becomes captured in the basket. The basket can then be retrieved taking the thrombus with it. Still other devices use a small corkscrew shaped device which is collapsed inside a catheter. The catheter is passed through the thrombus, the corkscrew is pushed out of the catheter allowing the device to expand, thereby capturing the thrombus for removal. Some corkscrew devices are simply “screwed” into the thrombus, then retracted into a catheter for removal before the corkscrew is retracted.
Known devices are disclosed in U.S. Pat. No. 7,052,500, US-2006/0,224,179 and US-2008/0,275,464.
Aspirating the thrombus into a catheter can cause breaking up of the thrombus during the procedure. Furthermore, where a thrombus is located in a very narrow vessel, the size of the catheter is too small and unable to house the thrombus within its lumen.